Identification of different classes of genome instability suppressor genes through analysis of DNA damage response markers

Abstract

Genetic studies in Saccharomyces cerevisiae have identified 266 genes and predicted an additional 38 genes that suppress the accumulation of spontaneous gross chromosomal rearrangements (GCRs). Here we identified mutations that induce two DNA damage response (DDR) markers, Hug1 expression and Ddc2 foci, and combined these data with other published screens identifying mutations inducing other DDR markers, including Rad52 foci and Rnr3 expression. Together, these data identify four categories of mutations: most mutations were DDR- GCR-, 356 were DDR+ GCR-, 72 were DDR- GCR+, and 157 were DDR+ GCR+. These results indicate that induction of DDR markers alone, while allowing DDR analysis, is not a reliable indicator of increased genome instability. They also guide further analysis of mechanistically distinct groups of GCR-inducing mutations, such as mutations that increase levels of GCR-inducing DNA damage and mutations that result in mis-repair of normal levels of DNA damage resulting in GCRs.